Beijing: A video of Liu Xiaobo being treated in jail was released on YouTube late on Wednesday, in what a source close to the Nobel Peace Prize winning activist said was a move by authorities to counter growing concerns over his care behind bars.

Liu, 61, was jailed for 11 years in 2009 for "inciting subversion of state power" after he helped write a petition known as "Charter 08" calling for sweeping political reforms.

He is being treated in a hospital in the northern city of Shenyang for late-stage liver cancer after he was granted medical parole, his lawyer told Reuters on Monday.

Liu Xiaobo. News18

In the three-minute video, Liu is shown playing badminton outside, being given a physical exam by prison guards and receiving medical treatment from doctors, as well as being visited by his wife Liu Xia.

In one clip, Liu speaks to Liu Xia via telephone as she sits behind glass in a visiting room. "I had a physical exam, they took blood, did Colour Doppler Imaging - it's very good," he says.

In another, a doctor asks Liu when he first knew he had tested positive for hepatitis B surface antigens, a test used to show if a patient suffers from hepatitis B virus, and Liu replies: "Over 20 years ago."

It is unclear when the scenes were filmed. The Prison Management Bureau in Liaoning, where Liu was jailed, could not be reached after office hours on Wednesday.

The Shenyang legal bureau, in a statement on its website on Wednesday, said signs he was unwell had been detected on 31 May and that he was immediately sent to the hospital where he was currently being treated by eight well-known domestic cancer experts. It said the cancer had spread to the rest of his body.

Several family members are with Liu in Shenyang, including his wife, who have "expressed satisfaction" with his treatment, and have also asked he be treated with traditional Chinese medicine which is now happening, the statement added.

Liu had a history of hepatitis B before entering jail, it said, citing prison records, adding he had received regular medical checks while in prison which had not previously found signs of hepatitis or tumours.

The video was posted on YouTube, which is blocked in China, by a user who had previously posted clips denouncing Guo Wengui, a controversial property tycoon who has made claims of high-level corruption within the ruling Communist Party.

When asked about the video, a source close to Liu and his wife told Reuters that Liu's statements in the film are "quotes without context," and noted that all the shots appeared to be taken with hidden cameras.

"They filmed this so they could create a propaganda clip," the source said.

"Maybe it was originally filmed to show their bosses; now it is being used to reply to critics of the Chinese government who say they did not do enough to stop Liu contracting advanced liver cancer."

State-run tabloid the Global Times said in an editorial on Thursday it was ridiculous to suggest China wanted to "murder" Liu.

"Liu is an ordinary prisoner. He ought to be grateful for extra help from the prison authorities, but he and his supporters have no right to demand preferential treatment," it said.

The US Ambassador to China Terry Branstad said on Wednesday the United States would like to see Liu treated elsewhere.

Amnesty International told Reuters on Tuesday that Liu Xia had told Chinese authorities she wanted her husband to receive medical treatment abroad.